Micrometer.



Patented Aug. 6, |901.

F. H. PIERPNT.

M I C R 0 M ET E R.

(Application med June 5, 1991.)

(No Model.)

UNITED STATES PATENT OFFICE.

' MONOTYPE MACHINE COMPANY,

LUMBIA.

OF WASHINGTON, DISTRICT OF CO- MICROMETER.

SPECIFICATION forming part of Letters Patent No. 679,779, dated August6, 1901.

Application filed June 5, 1901.

To all whom t may concern:

Be it known that I, FRANK HINMAN PIER- PONT, a citizen of the UnitedStates, residing at Horley, in the county of Surrey, England, haveinvented certain new and useful Improvements in Micrometers or MeasuringInstruments; and I do hereby declare the following to be a full, clear,and exact description of the same, reference being had to theaccompanying drawings, forming a part of this specication, and to theletters of reference marked thereon.

This invention relates to a new or improved micrometer, and has for itsobject to provide a micrometrical instrument which shall combinesimplicity and compactness of construction with ease and eiciency inoperation and in which the sources of error common to such devices arereduced to a minimum. Although not confined to this purpose, thisapparatus is more especially designed for the measurement of type, ofmatrices employed in typecasting machines, or of dies employed to stampsuch matrices.

A preferred construction of a measuring instrument according to thisinvention will now be described with reference to the accompanyingdrawings, in which- Figure 1 is a side elevation with a portion of theframe broken away. Fig. 2 is a plan View of the ocular disk.

A is the frame, preferably formed in one piece, carrying a microscope B,provided with a vertical illuminator C of any known type. Within theocular D, resting on or conveniently secured to the diaphragm D, is-atransparent disk E, upon which are engraved two diametrical lines atright angles to eachother, as shown at F F', Fig. 2. The object to beobserved, which in the figures is a die G for use in a matrix-stampingmachine, is held against the end surface J of a micrometerscrew mountedin the frame Aat right angles to the microscope B. The micrometerscrewcomprises a central screw-threaded portion J, with hardened ends J 2 J3.The portion J engages a thread, preferably formed in a nut A3, placedbetween hardened bushings A A2, forming bearings for the ends J 3 J 2,

semina. 63,282. (No model.)

respectively, and iixed in the frame A, so that the surface J of the endJ 2, with which the object to be measured is held in contact, lies-.inthe same vertical plane as the line F of the ocular-disk E or in a planeparallel thereto. On the end J3 of the micrometerscrew is mounted awheel or flanged disk K, the rim of which is graduated. ApointerLisprovided. A convenient form is that shown in the figures, in which thepointer, the front end of which is slotted to embrace the edge of thewheel-rim, is held in a recess in the frame A and kept in constantcontact with the Wheel-rim by the pressure of a spring L'. The wheel isprovided with a boss K', which serves as a handle to rotate the same andhas an annular recess to receive one end of a coiled spring K2, theother end of which presses against the `bushing A. The pressure of thisspring causes the wear of the lmicrometer-screw to take place on oneside only of the thread, and preferably the thread is provided with onestraight side and one inclined side, the thrust and wear coming on thestraight side. All possibility of error arising from slackness of thescrew is eliminated by the action of this spring, together with thepressure against the end of the screw of the object being measured.

Desirably a focusing-table H is provided adapted to be adj ustedvertically by rotating a nut H. This table forms a convenient gage forquickly bringing objects of the same length into focus.

The operation is as follows: The object to be measured is pressed by thehand against the surface J of the micrometer-screw. As

the cross-line F in the ocular is stationary and is always in focus, ithas the appearance of resting on the surface under observation.

'By manipulating the micrometer-screw the object thus held against thesurface J is caused to traverse laterally of the microscope, while thecross-line F has the appearance of moving across the surface to bemeasured, the amount of this movement being read directly from the scaleof the graduated wheel K. The pitch of the screw and the graduations ofthe scale may vary according to the use for which the instrument isdesigned. To facilitate reading, a convenient arrangement is to give themicrometer-screw a ten-pitch thread, and the Wheel is provided with athousand graduations.

The line F at right angles to the measuring-line F is not essential forthe purposes of this instrument, but is convenient for locating pointson the surface to be measured.

By employing the vertical illuminator those surfaces that are visible tothe eye are at right angles to the optical axis and the light falling onother surfaces is eitherl reflected outside of the instrument or isabsorbed in the walls of the microscope itself. Atype-die or type-matrixthus observed has the appearance of a bright character on a dullbackground. 'lhe sloping sides of the matrix or die are not visible, andthere is' therefore a distinct demarcation between the face of thecharacter and the surrounding surfaces.

Having thus described my invention, what- Iclaim as new, and desire tosecure by Letters Patent, is-

l. In a measuring instrument such as described, the combination with asupportingframe, of a microscope provided with an index-line and a gagemovable in a plane perpendicular to the axis of the microscope andhaving its contact-surface in a plane parallel to said index-line, asand for the purpose set forth.

2. In a measuring instrument, such as described, the combination with amicroscope fitted within a Vertical illuminator and an index-line, of amicrometer-gage supported to move in a plane at right angles to theoptical axis of the microscope and provided with an engaging orcontacting face in a plane parallel with the index-line, as and for thepur- 46 against which the object to be measured is directly held, saidend surface and the indexline lying in parallel vertical planes, as setforth.

4. In a measuring instrument such as deL scribed, the combination With amicroscope provided with a vertical illuminator and in dex-line, of afocusing-table and a microme ter-gage, the latter movable in a planetransverse to the optical axis of the microscope and provided with acontact-surface lying in a plane parallel to the said index-line, as andfor the purpose set forthi 5. In a measuring instrument such as de=scribed, the combination with a frame or standard anda microscopemounted therein, of a micrometer side gage mounted in an opening orbearing in the frame andV comprising a screw-shaft provided withcylindrical end portions, two sleeves each engaging one end of the shaftand forming a bearing therefor, a nut intermediate said sleeves, agraduated wheel secured to the rear end of said screw-shaft, and aspring interposed between saidwheel and the contiguous sleeve;substantially as describedi FRANK HINMAN PIERPONT.

' Witnesses:

W'. J. ROGERS, R. R. WILSON.

